Well the explorer is not hopeless, there was some talk a while back who was able to get high 20s highway. Make sure your general maintenance is up to date. Change the upper o2 sensors. Keep the torque converter locked up.
02 Saturn SL
for pics click the link below
LRR tires (are those 31's AT or highway tires?), higher tire pressure, coasting, shut it off at lights, don't use the a/c much, bigger spoiler in front, WAI, check your front end alignment, repack your bearings...run the LOWEST octane gas you can w/o knocking...check your vacuum lines, run some seafoam, get a better ratio rear end, dump mud flaps if you have 'em...
McIntyre's First Law: "Under the right circumstances, anything I tell you may be wrong."
O'Brien's First Corollary to McIntyre's First Law: "I don't know what the right circumstances are, either."
Electric fans are a solid MPG booster, takes a lot of load off the engine. Flexalite makes nice fans but their controllers have a history of melting down and sometimes catching fire. Supposedly this has been fixed, but... Normally I recommend a DC Control controller, but someone here reported that the guy that runs the company recently lost his manufacturer and is now having to hand make them, which means long delays in getting new ones.
Have you got a luggage rack? Remove it, it lowers the face you present to the wind. I don't know about Ford products, but there is a company that makes stainless steel plates for GM products that will bolt to the luggage rack roof holes for a clean look.
Then there's weight removal, the less weight you carry the less gas you burn. A fiberglass hood is a good way to cut about 30-40 pounds off, and if you have steel wheels changing them for aluminum will help. The idea here is to lower the overall weight of the wheel/tire package, which will also help acceleration. If you poke around all over the vehicle, you can find all sorts of things that aren't really necessary. Mind the ounces, and the pounds will follow . On my own 96 Tahoe (where most of what I'm posting came from) I was able to remove about 100 to 150lbs of unnecessary weight just by removing unnecessary bits, here and there.
If you are running the stock exhaust, a free-flowing exhaust that is not oversized will improve mileage. Install a set of long tube headers to emphasize low RPM power, then a stock diameter exhaust with a free-flowing muffler will help quite a bit. Too large will kill cylinder scavenging and reduce low-end power and economy (and is really suited to high RPM operation), too small will choke the engine off. To keep a stock sound, I suggest a Walker Quiet Flow muffler which will sound almost stock while allowing 30 percent more flow. Only problem is an Exploder is a box on wheels, which can result in resonance when you go to an aftermarket exhaust. A small glasspack muffler, in addition to the Quiet Flow muffler, behind the axle will almost completely eliminate this resonance.
You might go try to find a performance board aimed at Ford trucks and SUVs, and see what they are doing to increase the speed of their vehicles. While a performance board will be oriented to improving speed and performance, some of these ideas will improve MPG as well.
and i do think swapping the stock maf sensor housing is making a difference. im at 100 miles and still over half a tank, all city driving. i think ill get a good 10% increase. (which is like, 1 mpg for me )